Organic compound, and organic light emitting diode and organic light emitting display device including the same

ABSTRACT

an organic light emitting diode and an organic light emitting display device using the organic compound. The organic compound of the present invention is capable of reducing a driving voltage of an organic light emitting diode and improving an emitting efficiency and a lifetime of the organic light emitting diode and the organic light emitting display device including the organic compound.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a Divisional of co-pending U.S. patentapplication Ser. No. 15/717,414 filed on Sep. 27, 2017, which claims thepriority benefit of Korean Patent Application No. 10-2016-0125311 filedin Republic of Korea on Sep. 29, 2016, all of these applications arehereby incorporated by reference into the present application.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an organic compound and moreparticularly to an organic compound being capable of reducing a drivingvoltage of an organic light emitting diode and improving an emittingefficiency and a lifetime of the organic light emitting diode and theorganic light emitting display device including the organic compound.

Discussion of the Related Art

As requests for a flat panel display device having a small occupied areahave increased, an organic light emitting display (OLED) deviceincluding an organic light emitting diode has been the subject of recentresearch and development.

The organic light emitting diode emits light by injecting electrons froma cathode as an electron injection electrode and holes from an anode asa hole injection electrode into an emitting material layer (EML),combining the electrons with the holes, generating an exciton, andtransforming the exciton from an excited state to a ground state. Aflexible substrate, for example, a plastic substrate, can be used as abase substrate where elements are formed. Since the OLED device does notrequire a backlight assembly, the OLED device has low weight and lowpower consumption. Moreover, the OLED device can be operated at avoltage (e.g., 10V or below) lower than a voltage required to operateother display devices.

To efficiently inject the electron from the cathode into the EML, anorganic light emitting diode for the OLED device may further include anelectron injection layer (EIL) and an electron transporting layer (ETL)between the cathode and the EML. For example, an alkali halide material,e.g., LiF, or an organo-metallic material, e.g., lithium quinolate(Liq), may be used for the EIL. When an alkali metal or an alkali earthmetal may be included in the EIL, the alkali metal (or the alkali earthmetal) is diffused into the ETL with an electron such that the amount ofthe alkali metal (or the alkali earth metal) is reduced. As a result,the amount of the electron from the EIL into the ETL is decreased suchthat the driving voltage of the organic light emitting diode isincreased and the emitting efficiency of the organic light emittingdiode is decreased. In addition, the lifetime of the organic lightemitting diode is decreased.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an organic compoundand an organic light emitting diode and an organic light emittingdisplay (OLED) device including the same that substantially obviate oneor more of the problems due to limitations and disadvantages of therelated art.

An object of the present invention is to provide an organic compoundcapable of preventing the decrease of an electron transporting/injectionproperty and lifetime.

An object of the present invention is to provide an organic lightemitting diode and an OLED device having improved electrontransporting/injection property and lifetime.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, anorganic compound is, represented by following Formula:

wherein each of R₁ to R₂ is independently selected from the groupconsisting of hydrogen, substituted or non-substituted C₁-C₂₀ alkyl,substituted or non-substituted C₁-C₂₀ alkoxy, substituted ornon-substituted C₄-C₃₀ cycloalkyl, substituted or non-substituted C₄-C₃₀heterocycloalkyl, substituted or non-substituted C₆-C₆₀ homoaryl,substituted or non-substituted C₆-C₆₀ heteroaryl, substituted ornon-substituted C₆-C₆₀ homo-oxyaryl and substituted or non-substitutedC₆-C₆₀ hetero-oxyaryl, wherein each of L₁ and L₂ is independentlyselected from the group consisting of substituted or non-substitutedC₆-C₆₀ homoarylene and substituted or non-substituted C₆-C₆₀heteroarylene, wherein m is 0 (zero) or 1, and n is 1 or 2, wherein oneof X₁ to X₄ and X₉ is nitrogen atom, and the rest of X₁ to X₄ and X₉ areCH or CR₃, wherein one of X₅ to X₈ and X₁₀ is nitrogen atom, and therest of X₅ to X₈ and X₁₀ are CH or CR₄, and wherein each of R₃ and R₄ isindependently selected from the group consisting of hydrogen,substituted or non-substituted C₁-C₂₀ alkyl, substituted ornon-substituted C₁-C₂₀ alkoxy, C₁-C₂₀ alkyl amino, substituted ornon-substituted C₄-C₃₀ cycloalkyl, substituted or non-substituted C₄-C₃₀heterocycloalkyl, substituted or non-substituted C₆-C₆₀ homoaryl,substituted or non-substituted C₆-C₆₀ homo-oxyaryl and substituted ornon-substituted C₆-C₆₀ hetero-oxyaryl.

In another aspect, an organic light emitting diode comprises first andsecond electrodes facing each other; an emitting material layer betweenthe first and second electrodes; and an electron injection layer betweenthe emitting material layer and the second electrode and including theabove organic compound.

In another aspect, an organic light emitting diode comprises first andsecond electrodes facing each other; a first emitting part between thefirst and second electrodes and including a first emitting materiallayer and an electron transporting layer; a second emitting part betweenthe first emitting part and the second electrode and including a secondemitting material layer; and a first charge generation layer between thefirst and second emitting parts, wherein at least one of the electrontransporting layer and the first charge generation layer includes theorganic compound.

In another aspect, an organic light emitting display device comprises asubstrate; the above organic light emitting diode: and a thin filmtransistor between the substrate and the organic light emitting diodeand connected to the organic light emitting diode.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a schematic cross-sectional view of an organic light emittingdiode according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of an organic light emittingdiode according to a second embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of an organic light emittingdiode according to a third embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of an OLED device accordingto another embodiment of the present invention.

FIG. 5A, FIG. 5B and FIG. 5C are graphs showing emitting properties ofan organic light emitting diode including an organic compound in an EIL.

FIG. 6A, FIG. 6B and FIG. 6C are graphs showing emitting properties ofan organic light emitting diode including an organic compound in anN-type CGL.

FIG. 7A, FIG. 7B and FIG. 7C are graphs showing emitting properties ofan organic light emitting diode including an organic compound in anN-type CGL.

FIG. 8A, FIG. 8B and FIG. 8C are graphs showing emitting properties ofan organic light emitting diode including an organic compound in anN-type CGL.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments,examples of which are illustrated in the accompanying drawings.

An organic compound of the present invention includes a triazin core(first core) and a bipyridine moiety (second core) directly orindirectly connected (or linked) to the triazin core. The organiccompound is represented in Formula 1.

In Formula 1, each of R₁ to R₂ is independently selected from the groupconsisting of hydrogen, substituted or non-substituted C₁-C₂₀ alkyl,substituted or non-substituted C₁-C₂₀ alkoxy, substituted ornon-substituted C₄-C₃₀ cycloalkyl, substituted or non-substituted C₄-C₃₀heterocycloalkyl, substituted or non-substituted C₆-C₆₀ homoaryl,substituted or non-substituted C₆-C₆₀ heteroaryl, substituted ornon-substituted C₆-C₆₀ homo-oxyaryl and substituted or non-substitutedC₆-C₆₀ hetero-oxyaryl. In Formula 1, each of L₁ and L₂ is independentlyselected from the group consisting of substituted or non-substitutedC₆-C₆₀ homoarylene and substituted or non-substituted C₆-C₆₀heteroarylene. “m” is 0 (zero) or 1, and “n” is 1 or 2. In Formula 1,one of X₁ to X₄ and X₉ is nitrogen atom, and the rest of X₁ to X₄ and X₉are CH or CR₃. In addition, one of X₅ to X₈ and X₁₀ is nitrogen atom,and the rest of X₅ to X₈ and X₁₀ are CH or CR₄. Each of R₃ and R₄ may beindependently selected from the group consisting of hydrogen,substituted or non-substituted C₁-C₂₀ alkyl, substituted ornon-substituted C₁-C₂₀ alkoxy, C₁-C₂₀ alkyl amino, substituted ornon-substituted C₄-C₃₀ cycloalkyl, substituted or non-substituted C₄-C₃₀heterocycloalkyl, substituted or non-substituted C₆-C₆₀ homoaryl,substituted or non-substituted C₆-C₆₀ heteroaryl, substituted ornon-substituted C₆-C₆₀ homo-oxyaryl and substituted or non-substitutedC₆-C₆₀ hetero-oxyaryl.

For example, when m is 0, each of R₃ and R₄ may be hydrogen. On theother hand, when m is 1, R₃ may be hydrogen and R₄ may be heteroaryl(pyridine).

The Formula 1 may be represented by a Formula below.

In Formula 1, each of R₁ to R₂ is independently selected from the groupconsisting of hydrogen, substituted or non-substituted C₁-C₂₀ alkyl,substituted or non-substituted C₁-C₂₀ alkoxy, substituted ornon-substituted C₄-C₃₀ cycloalkyl, substituted or non-substituted C₄-C₃₀heterocycloalkyl, substituted or non-substituted C₆-C₆₀ homoaryl,substituted or non-substituted C₆-C₆₀ heteroaryl, substituted ornon-substituted C₆-C₆₀ homo-oxyaryl and substituted or non-substitutedC₆-C₆₀ hetero-oxyaryl. In Formula 1, each of L₁ and L₂ is independentlyselected from the group consisting of substituted or non-substitutedC₆-C₆₀ homoarylene and substituted or non-substituted C₆-C₆₀heteroarylene, and “m” is 0 (zero) or 1.

In Formula 1, one of X₁ to X₄ is nitrogen atom, and the rest of X₁ to X₄are CH or CR₃. In addition, one of X₅ to X₈ is nitrogen atom, and therest of X₅ to X₈ are CH or CR₄. Each of R₃ and R₄ may be independentlyselected from the group consisting of hydrogen, substituted ornon-substituted C₁-C₂₀ alkyl, substituted or non-substituted C₁-C₂₀alkoxy, C₁-C₂₀ alkyl amino, substituted or non-substituted C₄-C₃₀cycloalkyl, substituted or non-substituted C₄-C₃₀ heterocycloalkyl,substituted or non-substituted C₆-C₆₀ homoaryl, substituted ornon-substituted C₆-C₆₀ heteroaryl, substituted or non-substituted C₆-C₆₀homo-oxyaryl and substituted or non-substituted C₆-C₆₀ hetero-oxyaryl.

For example, when m is 0, each of R₃ and R₄ may be hydrogen. On theother hand, when m is 1, R₃ may be hydrogen and R₄ may be heteroaryl(pyridine).

In the term of “substituted,” the substituent may includehalogen-substituted or non-substituted alkyl group, halogen-substitutedor non-substituted alkoxy group, halogen, cyano group, carboxyl group,carbonyl group, amino group, alkylamino group, nitro group, hydrozylgroup, sulfonate group, alkyl silyl group, alkoxy silyl group, cycloakylsilyl group, aryl silyl group, substituted or non-substituted aryl groupor heteroaryl group, but it is not limited thereto.

The term “hetero,” which is used in heteroaryl, heteroarylene, and soon, means that at least one carbon atom in the aromatic ring oralicyclic ring is substituted by a heteroatom being selected from thegroup consisting of nitrogen atom (N), oxygen atom (O) and sulfur atom(S).

For example, when each of R₁, R₂, R₃ and R₄ is an aromatic ring, each ofR₁, R₂, R₃ and R₄ may be fused or non-fused homo-aromatic ring, such asphenyl, biphenyl, terphenyl, tetraphenyl, naphtyl, anthracenyl, indenyl,phenalenyl, phenanthrenyl, azulenyl, pyrenyl, fluorenyl, tetracenyl,indacenyl or spiro-fluorenyl, or fused or non-fused hetero-aromaticring, such as pyrrolyl, pyridyl (or pyridinyl), pyrimidyl (pyrimidinyl),pyrazinyl, pyridazinyl, triazinyl, tetrazinyl, imidazolyl, pyrazolyl,indolyl, carbazolyl, benzocarbazolyl, dibenzocarbazolyl,indolocarbazolyl, indenocarbazolyl, quinolinyl, iso-quinolinyl,phthalazinyl, quinoxalinyl, cinnolinyl, quinazolinyl, phthalazinyl,benzoquinolinyl, benzo iso-quinolinyl, benzoqhinazolinyl,benzoquinoxalinyl, acrydinyl, phenanthrolinyl, furanyl, pyranyl,oxazinyl, oxazolyl, oxadiazolyl, triazolyl, dioxynyl, benzofuranyl,dibenzofuranyl, thio-pyranyl, thiazinyl, thiophenyl or N-substitutedspiro-fluorenyl. In the organic compound of the exemplary embodiment ofthe present invention, each of R₁ and R₂ may be phenyl or biphenyl.

For example, each of R₁ to R₄ may be independently selected from thegroup consisting of phenyl, alkylphenyl, biphenyl, alkylbiphenyl,halophenyl, alkoxyphenyl, haloalkoxyphenyl, cyanophenyl, silylphenyl,naphthyl, alkylnaphthyl, halonaphthyl, cyanonaphthyl, silylnaphthyl,phenylnaphthyl, pyridyl, alkylpyridyl, halopyridyl, cyanopyridyl,alkoxypyridyl, silylpyridyl, phenylpyridyl, pyrimidyl, halopyrimidyl,cyanopyridyl, alkoxypyrimidyl, phenylpyrimidyl, quinolinyl,isoquinolinyl, phenylquinolinyl, quinoxalinyl, pyrazinyl, quinazolinyl,naphthyridinyl, benzothiophenyl, benzofuranyl, dibenzothiophenyl,arylthiazolyl, dibenzofuranyl, fluorenyl, carbazoyl, imidazolyl,carbolinyl, phenanthrenyl, terphenyl, terpyridyl, phenylterpyridyl,triphenylenyl, fluoranthenyl and diazafluorenyl.

The carrier mobility of the organic compound may be controlled by L₁ andL₂ as the linker. Each of L₁ and L₂ may be an aromatic linker. Forexample, each of L₁ and L₂ may be one substituted or non-substitutedC₆-C₆₀ homoarylene and substituted or non-substituted C₆-C₆₀heteroarylene. Preferably, each of L₁ and L₂ may be one substituted ornon-substituted C₆-C₆₀ homoarylene.

For example, each of L₁ and L₂ may be independently selected from agroup consisting of phenylene, biphenylene, terphenylene,tetraphenylene, indenylene, naphthylene, azulenylene, indacenylene,acenaphthylene, fluorenylene, spiro-fluorenylene, phenalenylene,phenanthrenylene, anthracenylene, fluoranthrenylene, triphenylenylene,pyrenylene, chrysenylene, naphthacenylene, picenylene, perylenylene,pentaphenylene, hexacenylene, pyrrolylene, imidazolylene, pyrazolylene,pyridinylene, pyrazinylene, pyrimidinylene, pyridazinylene,isoindolylene, indolylene, indazolylene, purinylene, quinolinylene,isoquinolinylene, benzoquinolinylene, phthalazinylene,naphthyridinylene, quinoxalinylene, quinazolinylene, benzoquinolinylene,benzo iso-quinolinylene, benzoquinazolinylene, benzoquinoxalinylene,cinnolinylene, phenanthridinylene, acridinylene, phenanthrolinylene,phenazinylene, benzoxazolylene, benzimidazolylene, furanylene,benzofuranylene, thiophenylene, benzothiophenylene, thiazolylene,isothiazolylene, benzothiazolylene, isoxazolylene, oxazolylene,triazolylene, tetrazolylene, oxadiazolylene, triazinylene,dibenzofuranylene, dibenzothiophenylene, carbazolylene,benzocarbazolylene, dibenzocarbazolylene, indolocarbazolylene,indenocarbazolylene, imidazopyrimidinylene and imidazopyridinylene.

For example, each of L₁ and L₂ may be selected from the group consistingof phenylene, alkylphenylene, cyanophenylene, naphthylene,alkylnaphthylene, biphenylene, alkyl biphenylene, anthracenylene,pyrenylene, benzothiophenylene, benzofuranylene, dibenzothiophenylene,arylthiazolylene, dibenzofuranylene, fluorenylene and triphenylene.

When the number of rings of L₁ and L₂ is increased, the conjugationlength of the organic compound is increased such that the energy bandgap of the organic compound is decreased. Accordingly, the number ofrings of L₁ and L₂ may be 1 to 3. To improve the electroninjection/transporting property of the organic compound, L₁ and L₂ maybe a 5-numbered atom ring to a 7-numbered atom ring, and beneficially a6-numbered atom ring. In this instance, each of L₁ and L₂ may phenylene,pyrrolylene, imidazolylene, pyrazolylene, pyrazinylene, pyrimidinylene,pyridazinylene, furanylene or thiophenylene, but it is not limitedthereto.

The organic compound in the Formula 1 may be one of the materials inFormula 2.

Since the organic compound of the present invention includes the triazincore having three nitrogen atoms, each of which have a rich electronproperty, an electron transporting (or mobility) property of the organiccompound is increased such that the electron is efficiently transportedby the organic compound. In addition, in the organic compound, thebipyridine moiety, which has high electronegativity, is connected(combined or linked) to the triazin core via at least one linker suchthat the electron transporting property of the organic compound isfurther increased. Moreover, since the triazin core and the bipyridinemoiety are separated by the at least one linker, the electronlocalization problem is prevented such that the electron uniformlyexists in the organic compound. As a result, the electron from a cathodeor an N-type charge generation layer (CGL) is efficiently injected ortransported into an electron transporting layer (ETL) or an emittingmaterial layer (EML). Accordingly, when the organic compound is used forat least one of an electron injection layer (EIL), the ETL and theN-type CGL of an organic light emitting diode, the electroninjection/transporting property in the organic light emitting diode isincreased such that there are advantages in the driving voltage, thelifetime and the emitting efficiency.

In addition, since the organic compound (e.g., the nitrogen atom in thetriazin core) is combined with the alkali metal or the alkali earthmetal in the ETL or the N-type CGL, the diffusion of the alkali metal orthe alkali earth metal into the EML or the P-type CGL is prevented.Further, since the nitrogen atom of the triazin core in the organiccompound is combined or bonded with the alkali metal or the alkali earthmetal as a dopant in the ETL or an N-type CGL to form a gap state, theelectron transporting property of the ETL or the N-type CGL is furtherimproved.

As mentioned above, the organic compound of the present inventionincludes the triazin core, which has excellent electrontransporting/injection property, and the bipyridine moiety, which hasexcellent electronegativity, connected to the each other via at leastone linker. Accordingly, the organic compound is used for a layer of theorganic light emitting diode requiring the electron transportingproperty and/or the electron injection property.

FIG. 1 is a schematic cross-sectional view of an organic light emittingdiode according to a first embodiment of the present invention.

As shown in FIG. 1, the organic light emitting diode D1 includes a firstelectrode 180, a second electrode 184, an organic emitting layer 182(e.g., an organic material layer or an emitting part) between the firstand second electrodes 180 and 184. The organic emitting layer 182includes a hole injection layer (HIL) 210, a hole transporting layer(HTL) 220, an emitting material layer (EML) 230, an electrontransporting layer (ETL) 240 and an electron injection layer (EIL) 250sequentially stacked on the first electrode 180. Namely, the organiclight emitting diode D1 of the first embodiment of the present inventionincludes a single emitting part.

The first electrode 180 is the anode for injecting a hole and includes ahigh work function conductive material, e.g., indium-tin-oxide (ITO),indium-zinc-oxide (IZO) or zinc oxide (ZnO). The second electrode 184 isthe cathode for injecting an electron and includes a low work functionconductive material, e.g., aluminum (Al), magnesium (Mg) or Al—Mg alloy.

The HIL 210 is positioned between the first electrode 180 and the HTL220. An interface property between the first electrode 180 of aninorganic material and the HTL 220 of an organic material is improved bythe HIL 210. For example, the HIL 210 may include one of4,4′,4″-tris(3-methylphenylphenylamino)triphenylamine (MTDATA), copperphthalocyanine (CuPc), tris(4-carbazoyl-9-yl-phenyl)amine (TCTA),N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4″-diamine (NPB orNPD), 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HATCN),1,3,5-tris[4-(diphenylamino)phenyl]benzene (TDAPB),poly(3,4-ethylenedioxythiphene)polystyrene sulfonate (PEDOT/PSS),2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) andN-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine.

The HIL 210 may have a thickness of about 1 to 150 nm. The holeinjection property may be improved with the thickness above 1 nm, and anincrease of the driving voltage resulting from an increase of thethickness of the HIL 210 may be prevented with the thickness below 150nm. The HIL 210 may be omitted.

The HTL 220 is positioned between the HIL 210 and the EML 230. Forexample, the HTL 220 may include a hole transporting material such asN,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD),MTDATA, TCTA, NPD or 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP). The HTL220 may have a double-layered structure of different hole transportingmaterials.

The HTL 220 may have a thickness of about 1 to 150 nm. The holetransporting property may be improved with the thickness above 1 nm, andan increase of the driving voltage resulting from an increase of thethickness of the HTL 220 may be prevented with the thickness below 150nm.

The EML 230 may include a host and a dopant. For example, when the EML230 emits blue light, a fluorescent host, such as anthracene derivative,pyrene derivative or perylene derivative, and a fluorescent dopant areused for the EML 230.

For example, the fluorescent host for the EML 230 may be selected fromthe group consisting of 4,4′-bis(2,2′-diphenylyinyl)-1,1′-biphenyl(DPVBi), 9,10-di-(2-naphtyl)anthracene (ADN),2,5,8,11-tetra-t-butylperylene (TBADN),2-tert-butyl-9,10-di(2-naphthyl)anthracene,2-methyl-9,10-di(2-naphtyl)anthracene (MADN) and2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TBPi).

For example, the fluorescent dopant for the EML 230 may be selected fromthe group consisting of4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl (BCzVBi),2,5,8,11-tetra(tert-butyl)perylene (TBP) anddiphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]-amine (BD-1).

When the EML 230 emits green light or red light, the EML 230 may includea phosphorescent host, e.g., carbazole derivative, and a phosphorescentdopant, e.g., a metal (iridium) complex. The dopant may have a weight %of about 1 to about 30 with respect to the host.

The ETL 240 is positioned between the EML 230 and the second electrode184, and the EIL 250 is positioned between the ETL 240 and the secondelectrode 184.

The ETL 240 may include a derivative of oxadiazole, triazole,phenanthroline, benzoxazole, benzothiazole, benzimidazole and triazine.For example, the ETL 240 may include an electron transporting materialselected from a group consisting of tris-(8-hydroxyquinoline aluminum(Alq3), 2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD),spiro-PBD, Liq,2-[4-(9,10-Di-2-naphthalenyl-2-anthracenyl)phenyl]-1-phenyl-1H-benzimidazol,3-(biphenyl-4-yl)-5-(4-tertbutylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ), 4,7-diphenyl-1,10-phenanthroline (Bphen), tris(phenylquinoxaline(TPQ) and 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBI), but it isnot limited thereto.

Alternatively, the ETL 240 may include the above electron transportingmaterial and the organic compound of the present invention as a dopant.In this instance, the organic compound may have a weight % of about 1 to30 with respect to the electron transporting material, but it is notlimited thereto.

The ETL 240 may have a thickness of about 1 to 150 nm. The electrontransporting property may be improved with the thickness above 1 nm, andan increase of the driving voltage resulting from an increase of thethickness of the ETL 240 may be prevented with the thickness below 150nm.

An electron injection is improved by the EIL 250. The EIL 250 mayinclude the organic compound of the present invention. A dopant, e.g.,an alkali metal or an alkali earth metal, may be doped into the EIL 250to improve the electron injection property. The dopant may have a weight% of about 1 to 20 with respect to the organic compound, but it is notlimited thereto. For example, the dopant may be one of Li, Na, K, Cs,Mg, Sr, Ba and Ra. Alternatively, the dopant may be a metal compound,i.e., an alkali metal compound or an alkali earth metal compound, suchas Liq, LiF, NaF, KF, RbF, CsF, FrF, BeF₂, MgF₂, CaF₂, SrF₂, BaF₂ orRaF₂.

The EIL 250 may have a thickness of about 1 to 50 nm. The electroninjection property may be improved with the thickness above 1 nm, and anincrease of the driving voltage resulting from an increase of thethickness of the EIL 250 may be prevented with the thickness below 50nm.

Since the organic compound of the present invention includes the triazincore having three nitrogen atoms, each of which have a rich electronproperty, an electron transporting (or mobility) property of the organiccompound is increased such that the electron is efficiently transportedby the organic compound. In addition, in the organic compound, thebipyridine moiety, which has high electronegativity, is connected(combined or linked) to the triazin core via at least one linker suchthat the electron transporting property of the organic compound isfurther increased. Accordingly, when the organic compound is used for atleast one of the EIL and the ETL of an organic light emitting diode, theelectron injection/transporting property into the EML in the organiclight emitting diode is increased such that there are advantages in thedriving voltage, the lifetime and the emitting efficiency.

On the other hand, the organic compound of the present invention may beapplied to a tandem structure organic light emitting diode emitting thewhite light. The tandem structure white organic light emitting diode maybe used for a lighting apparatus, a thin light source, a backlight unitof a liquid crystal display device and a full color display deviceincluding a color filter.

In the white organic light emitting diode, properties of color purityand color stability as well as an emitting efficiency and a lifetime areimportant considerations. For example, the white organic light emittingdiode may be classified into a single-layered emission structure and amulti-layered emission structure. To achieve a long lifetime whiteorganic light emitting diode, the white organic light emitting diodehaving a stack structure of at least two emitting parts may be used.This structure may be referred to as the tandem structure.

FIG. 2 is a schematic cross-sectional view of an organic light emittingdiode according to a second embodiment of the present invention.

As shown in FIG. 2, the organic light emitting diode D2, which includestwo emitting parts, includes a first electrode 180, a second electrode184, an organic emitting layer 182 between the first and secondelectrodes 180 and 184 and including first and second emitting parts ST1and ST2 and a charge generation layer (CGL) 330.

The first electrode 180 is the anode for injecting a hole and includes ahigh work function conductive material, e.g., ITO, IZO or ZnO. Thesecond electrode 184 is the cathode for injecting an electron andincludes a low work function conductive material, e.g., Al, Mg or Al—Mgalloy.

The CGL 330 is positioned between the first and second emitting partsST1 and ST2. Namely, the first emitting part ST1, the CGL 330 and thesecond emitting part ST2 are sequentially stacked on the first electrode180. In other words, the first emitting part ST1 is positioned betweenthe first electrode 180 and the CGL 330, and the second emitting partST2 is positioned between the second electrode 184 and the CGL 330.

The first emitting part ST1 may include an HIL 312, a first HTL 314, afirst EML 316 and a first ETL 318 sequentially stacked on the firstelectrode 180. Namely, the HIL 312 and the first HTL 314 are positionedbetween the first electrode 180 and the first EML 316. The HIL 312 ispositioned between the first electrode 180 and the first HTL 314, andthe first HTL 314 is positioned between the HIL 312 and the first EML316. In addition, the first ETL 318 is positioned between the first EML316 and the CGL 330.

A hole injection from the first electrode 180 into the first EML 316 isimproved by the HIL 312. The HIL 312 may include at least one selectedfrom the group consisting of MTDATA, CuPc, TCTA, NPD, HATCN, TDAPB),PEDOT/PSS, F4TCNQ andN-(biphenyl-4-yl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazole-3-yl)phenyl)-9H-fluorene-2amine.

The HIL 312 may have a thickness of about 1 to 150 nm. The holeinjection property may be improved with the thickness above 1 nm, and anincrease of the driving voltage resulting from an increase of thethickness of the HIL 312 may be prevented with the thickness below 150nm. The HIL 312 may be omitted according to the structure or property ofthe organic light emitting diode.

A hole transporting is improved by the first HTL 314. The first HTL 314may include at least one selected from a group consisting of TPD, TCTA,MTDATA, NPD and CBP, but it is not limited thereto. The first HTL 314may have a single-layered structure or a multi-layered structure.

The first HTL 314 may have a thickness of about 1 to 150 nm. The holetransporting property may be improved with the thickness above 1 nm, andan increase of the driving voltage resulting from an increase of thethickness of the first HTL 314 may be prevented with the thickness below150 nm.

The first EML 316 may be a blue EML. Alternatively, the first EML 316may be a red EML, a green EML or a yellow EML. When the first EML 316 isthe blue EML, the first EML 316 may be a blue EML, a dark blue EML or asky blue EML. In addition, the first EML 316 may be a double-layeredstructure of the blue EML and the red EML, the blue EML and yellow-greenEML, or the blue EML and the green EML.

When the first EML 316 is the red EML, the first EML 316 may be aphosphorescent EML including a host, e.g.,4,4′-bis(carbazol-9-yl)biphenyl (CBP), and at least one dopant selectedfrom the group consisting of bis(1-phenylisoquinoline)acetylacetonateiridium (PIQIr(acac), bis(1-phenylquinoline)acetylacetonateiridium(PQIr(acac) and tris(1-phenylquinoline)iridium(PQIr) andoctaethylporphyrin platinum (PtOEP), but it is not limited thereto.Alternatively, the first EML 316 may be a fluorescent EML includingPBD:Eu(DBM)₃(Phen) or perylene. In this instance, the first emittingpart ST1 has an emission peak range of about 600 to 650 nm.

When the first EML 316 is the green EML, the first EML 316 may be aphosphorescent EML including a host, e.g., CBP, and a dopant of iridiumcomplex, but it is not limited thereto. Alternatively, the first EML 316may a fluorescent EML including tris(8-hydroxyquinolinato)aluminum(Alq₃). In this instance, the first emitting part ST1 has an emissionpeak range of about 510 to 570 nm.

When the first EML 316 is the blue EML, the first EML 316 may be aphosphorescent EML including a host, e.g., CBP, and a dopant of iridiumcomplex, but it is not limited thereto. Alternatively, the first EML 316may a fluorescent EML including spiro-DPVBi, Spiro-CBP, distyryl benzene(DSB), distyryl arene (DSA), PFO-based polymer or PPV-based polymer. Asmentioned above, the first EML 316 may be a sky blue EML or deep blue(dark blue) EML. In this instance, the first emitting part ST1 has anemission peak range of about 440 to 480 nm.

On the other hand, to improve the emitting efficiency (red efficiency),the first emitting part ST1 may include two EMLs. For example, the firstemitting part ST1 may include the blue EML and the red EML. In thisinstance, the first emitting part ST1 has an emission peak range ofabout 440 to 650 nm.

In addition, the first EML 316 may have a single-layered structure ofthe yellow-green EML or a double-layered structure of the yellow-greenEML and the green EML. In this instance, the first EML 316 may includeat least one host selected from a group consisting of CBP andbis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium (BAlq) and aphosphorescent yellow-green dopant. The first emitting part ST1 has anemission peak range of about 510 to 590 nm.

When the first emitting part ST1 includes two EMLs of the yellow-greenEML and the red EML to improve the emitting efficiency (red efficiency),the first emitting part ST1 has an emission peak range of about 510 to650 nm.

An electron transporting is improved by the first ETL 318. The first ETL318 may include an electron transporting material selected from a groupconsisting of Alq3, PBD, spiro-PBD, Liq,2-[4-(9,10-Di-2-naphthalenyl-2-anthracenyl)phenyl]-1-phenyl-1H-benzimidazol,TAZ, Bphen, TPQ and TPBI. Alternatively, the first ETL 318 may includethe above electron transporting material and the organic compound of thepresent invention as a dopant.

The first ETL 318 may have a thickness of about 1 to 150 nm. Theelectron transporting property may be improved with the thickness above1 nm, and an increase of the driving voltage resulting from an increaseof the thickness of the first ETL 318 may be prevented with thethickness below 150 nm.

The second emitting part ST2 may include a second HTL 322, a second EML324, a second ETL 326 and an EIL 328. The second HTL 322 is positionedbetween the CGL 330 and the second EML 324, and the second ETL 326 ispositioned between the second EML 324 and the second electrode 184. Inaddition, the EIL 328 is positioned between the second ETL 326 and thesecond electrode 184.

The second HTL 322 and the second ETL 326 may be same as or differentfrom the first HTL 314 and the first ETL 318 in the first emitting partST1, respectively.

The second EML 324 may be red, green, blue or yellow-green EML. Forexample, when the first EML 316 is the blue EML, the second EML 324 maybe yellow-green EML. Alternatively, the first EML 316 may be theyellow-green EML, and the second EML 324 may be the blue EML.

When the second EML 324 is the yellow-green EML, the second EML 324 mayhave a single-layered structure of the yellow-green EML or adouble-layered structure of the yellow-green EML and the green EML.

For example, the single-layered second EML 324 may include at least onehost selected from a group consisting of CBP andbis(2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminium (BAlq) and aphosphorescent yellow-green dopant, but it is not limited thereto.

An electron injection is improved by the EIL 328. The EIL 328 mayinclude an electron injection material being selected from a groupconsisting of Alq3, PBD, TAZ and BAlq, but it is not limited thereto.Alternatively, the EIL 328 may include the organic compound of thepresent invention.

The EIL 328 may further include a metal compound as a dopant. The dopantmay be one of Liq, LiF, NaF, KF, RbF, CsF, FrF, BeF₂, MgF₂, CaF₂, SrF₂,BaF₂ or RaF₂, but it is not limited thereto. The dopant may have aweight % of about 1 to 20 with respect to the organic compound, but itis not limited thereto.

The EIL 328 may have a thickness of about 1 to 50 nm. The electroninjection property may be improved with the thickness above 1 nm, and anincrease of the driving voltage resulting from an increase of thethickness of the EIL 328 may be prevented with the thickness below 50nm.

In the tandem structure organic light emitting diode D2, to increase thecurrent efficiency generating from each of the EMLs 316 and 324 andefficiently distribute the charge, the CGL 330 is positioned between thefirst emitting part ST1 and the second emitting part ST2. Namely, thefirst and second emitting parts ST1 and ST2 are connected by the CGL330. The CGL 330 may be a P-N junction type CGL including an N-type CGL330N and a P-type CGL 330P.

The N-type CGL 330N is positioned between the first ETL 318 and thesecond HTL 322, and the P-type CGL 330P is positioned between the N-typeCGL 330N and the second HTL 322. The CGL 330 generates a charge orseparates a charge into a hole and an electron such that the hole andthe electron are provided into the first and second emitting parts ST1and ST2.

The N-type CGL 330N provides the electron into the first ETL 318 of thefirst emitting part ST1, and the first ETL 318 provide the electron intothe first EML 316 of the first emitting part ST1. On the other hand, theP-type CGL 330P provide the hole into the second HTL 322 of the secondemitting part ST2, and the second HTL 322 provide the hole into thesecond EML 324 of the second emitting part ST2.

The P-type CGL may include an organic material and a dopant, e.g., ametal or a p-type dopant. For example, the metal as the dopant may beselected from the group consisting of Al, Cu, Fe, Pb, Zn, Au, Pt, W, In,Mo, Ni, Ti and their alloy. In addition, the generally known materialsmay be used as the p-type dopant and the organic material. For example,the p-type dopant may be selected from the group consisting of F₄-TCNQ,iodine, FeCl₃, FeF₃ and SbCl₅, and the organic material may be selectedfrom the group consisting of NPB, TPD,N,N,N′,N′-tetranaphthalenyl-benzidine (TNB) and HAT-CN.

In the tandem structure organic light emitting diode, when the electronsare transported from the N-type CGL 330N into the first ETL 318, thedriving voltage is increased because of a lowest unoccupied molecularorbital (LUMO) energy level difference between each of the first ETL 318and the N-type CGL 330N.

To overcome the above problem, at least one of the first ETL 318 and theN-type CGL 330N includes an organic compound of the present invention.In addition, each of the first ETL 318 and the N-type CGL 330N mayfurther include alkali metal, alkali metal compound, alkali earth metalor alkali earth metal compound as a dopant.

By doping the above dopant into the first ETL 318 and/or the N-type CGL330N, the electron transporting/injection property may be furtherimproved. For example, when the dopant is doped into the N-type CGL330N, the organic compound is combined or bonded with the dopant, e.g.,alkali metal, alkali metal compound, alkali earth metal or alkali earthmetal compound, in the N-type CGL to form a gap state. As a result, theenergy difference between the N-type CGL 330N and the P-type CGL 330P isdecreased such that an electron transporting/injection property from theN-type CGL 330N into the first ETL is improved.

For example, the dopant may be one of Liq, LiF, NaF, KF, RbF, CsF, FrF,BeF₂, MgF₂, CaF₂, SrF₂, BaF₂ or RaF₂, may be doped. The dopant may havea weight % of about 1 to 20 with respect to the organic compound, but itis not limited thereto.

Since the organic compound of the present invention includes the triazincore having three nitrogen atoms, each of which have a rich electronproperty, an electron transporting (or mobility) property of the organiccompound is increased such that the electron is efficiently transportedby the organic compound. In addition, in the organic compound, thebipyridine moiety, which has high electronegativity, is connected(combined or linked) to the triazin core via at least one linker suchthat the electron transporting property of the organic compound isfurther increased. Moreover, since the triazin core and the bipyridinemoiety are separated by the at least one linker, the electronlocalization problem is prevented such that the electron uniformlyexists in the organic compound.

As a result, the electron from the N-type CGL is efficiently injected ortransported into the ETL. Namely, in the present invention, the ETLand/or the N-type CGL include the organic compound having the triazincore and bipyridine moiety, the electron injection/transporting propertyin the organic light emitting diode is increased such that there areadvantages in the driving voltage, the lifetime and the emittingefficiency.

In addition, since the organic compound of the present inventionincludes the nitrogen atom having a relatively electron rich sp² hybridorbital, the nitrogen atom in the organic compound is combined or bondedwith the dopant, e.g., alkali metal, alkali metal compound, alkali earthmetal or alkali earth metal compound, in the N-type CGL to form a gapstate. As a result, the electron is efficiently transported from theN-type CGL into the ETL.

FIG. 3 is a schematic cross-sectional view of an organic light emittingdiode according to a third embodiment of the present invention.

Referring to FIG. 3, an organic light emitting diode D3 includes a firstelectrode 180, a second electrode 184, an organic emitting layer 182between the first and second electrodes 180 and 184 and including firstto third emitting parts ST1, ST2 and ST3 and first and second CGLs 430and 450. Alternatively, four or more emitting parts and three or moreCGLs may be disposed between the first and second electrodes 180 and184.

As mentioned above, the first electrode 180 is the anode for injecting ahole and includes a high work function conductive material, e.g., ITO,IZO or ZnO. The second electrode 184 is the cathode for injecting anelectron and includes a low work function conductive material, e.g., Al,Mg or Al—Mg alloy.

The first and second CGLs 430 and 450 are positioned between the firstand second emitting parts ST1 and ST2 and the second and third emittingparts ST2 and ST3, respectively. Namely, the first emitting part ST1,the first CGL 430, the second emitting part ST2, the second CGL 450 andthe third emitting part ST3 are sequentially stacked on the firstelectrode 180. In other words, the first emitting part ST1 is positionedbetween the first electrode 180 and the first CGL 430, and the secondemitting part ST2 is positioned between the First and Second CGLs 430and 450. In addition, the third emitting part ST3 is positioned betweenthe second electrode 184 and the second CGL 450.

The first emitting part ST1 may include an HIL 412, a first HTL 414, afirst EML 416 and a first ETL 418 sequentially stacked on the firstelectrode 180. Namely, the HIL 412 and the first HTL 414 are positionedbetween the first electrode 180 and the first EML 416, and the HIL 412is positioned between the first electrode 180 and the first HTL 414. Inaddition, the first ETL 418 is positioned between the first EML 416 andthe first CGL 430.

The HIL 412, the first HTL 414, the first EML 416 and the first ETL 418may have substantially the same property and structure as those in FIG.2. For example, the first EML 416 may be a blue EML such that the firstemitting part ST1 may have an emission peak range of about 440 to 480nm.

The second emitting part ST2 may include a second HTL 422, a second EML424 and a second ETL 426. The second HTL 422 is positioned between thefirst CGL 430 and the second EML 424, and the second ETL 426 ispositioned between the second EML 424 and the second CGL 450.

The second HTL 422, second EML 424 and the second ETL 426 may havesubstantially the same property and structure as those in FIG. 2. Forexample, the second EML 424 may be a yellow-green EML such that thesecond emitting part ST2 may have an emission peak range of about 510 to590 nm.

The third emitting part ST3 may include a third HTL 442, a third EML444, a third ETL 446 and an EIL 448. The third HTL 442 is positionedbetween the second CGL 450 and the third EML 444, and the third ETL 446is positioned between the third EML 444 and the second electrode 184. Inaddition, the EIL 448 is positioned between the third ETL 446 and thesecond electrode 184.

The third HTL 442, the third ETL 446 and the EIL 448 may havesubstantially the same property and structure as the second HTL 422, thesecond ETL 426 and the EIL 428 in FIG. 2.

The third EML 444 may have substantially the same property as the firstEML 416 or the second EML 424. For example, the third EML 444 may be ablue EML such that the third emitting part ST3 may have an emission peakrange of about 440 to 480 nm.

The first CGL 430 is positioned between the first emitting part ST1 andthe second emitting part ST2, and the second CGL 450 is positionedbetween the second emitting part ST2 and the third emitting part ST3.Each of the first and second CGLs 430 and 450 may be a P-N junction typeCGL. The first CGL 430 includes an N-type CGL 430N and a P-type CGL430P, and the second CGL 450 includes an N-type CGL 450N and a P-typeCGL 450P.

In the first CGL 430, the N-type CGL 430N is positioned between thefirst ETL 418 and the second HTL 422, and the P-type CGL 430P ispositioned between the N-type CGL 430N and the second HTL 422.

In the second CGL 450, the N-type CGL 450N is positioned between thesecond ETL 426 and the third HTL 442, and the P-type CGL 450P ispositioned between the N-type CGL 450N and the third HTL 442.

Each of the first and second CGLs 430 and 450 generates a charge orseparates a charge into a hole and an electron such that the hole andthe electron are provided into the first to third emitting parts ST1 toST3.

Namely, in the first CGL 430, the N-type CGL 430N provides the electroninto the first ETL 418 of the first emitting part ST1, and the P-typeCGL 430P provide the hole into the second HTL 422 of the second emittingpart ST2. In addition, in the second CGL 450, the N-type CGL 450Nprovides the electron into the second ETL 426 of the second emittingpart ST2, and the P-type CGL 450P provide the hole into the third HTL442 of the third emitting part ST3.

Each of the P-type CGLs 430P and 450P may include an organic materialand a dopant, e.g., a metal or a p-type dopant. For example, the metalas the dopant may be selected from the group consisting of Al, Cu, Fe,Pb, Zn, Au, Pt, W, In, Mo, Ni, Ti and their alloy. In addition, thegenerally known materials may be used as the p-type dopant and theorganic material. For example, the p-type dopant may be selected fromthe group consisting of F₄-TCNQ, iodine, FeCl₃, FeF₃ and SbCl₅, and theorganic material may be selected from the group consisting of NPB, TPD,N,N,N′,N′-tetranaphthalenyl-benzidine (TNB) and HAT-CN.

When the electrons are transported from the N-type CGLs 430N and 450Ninto the first and second ETLs 418 and 426, the driving voltage isincreased because of a lowest unoccupied molecular orbital (LUMO) energylevel difference between each of the first and second ETLs 418 and 426and each of the N-type CGLs 430N and 450N.

To overcome the above problem, at least one of the first and second ETLs418 and 426 and the N-type CGLs 430N and 450N includes an organiccompound represented in Formula 1 (or Formula 2). In addition, each ofthe first and second ETLs 418 and 426 and the N-type CGLs 430N and 450Nmay further include a dopant, e.g., alkali metal, alkali metal compound,alkali earth metal or alkali earth metal compound.

For example, the dopant may include one of Liq, LiF, NaF, KF, RbF, CsF,FrF, BeF₂, MgF₂, CaF₂, SrF₂, BaF₂ and RaF₂. The dopant may have a weight% of about 1 to 20 with respect to the organic compound, but it is notlimited thereto.

Since the organic compound of the present invention includes the triazincore having three nitrogen atoms, each of which have a rich electronproperty, an electron transporting (or mobility) property of the organiccompound is increased such that the electron is efficiently transportedby the organic compound. In addition, in the organic compound, thebipyridine moiety, which has high electronegativity, is connected(combined or linked) to the triazin core via at least one linker suchthat the electron transporting property of the organic compound isfurther increased. Moreover, since the triazin core and the bipyridinemoiety are separated by the at least one linker, the electronlocalization problem is prevented such that the electron uniformlyexists in the organic compound. As a result, the electron from a cathodeor an N-type charge generation layer (CGL) is efficiently injected ortransported into an electron transporting layer (ETL) or an emittingmaterial layer (EML). Accordingly, when the organic compound is used forat least one of an electron injection layer (EIL), the ETL and theN-type CGL of an organic light emitting diode, the electroninjection/transporting property in the organic light emitting diode isincreased such that there are advantages in the driving voltage, thelifetime and the emitting efficiency.

In addition, since the organic compound of the present inventionincludes the nitrogen atom having a relatively electron rich sp² hybridorbital, the nitrogen atom in the organic compound is combined or bondedwith the dopant, e.g., alkali metal, alkali metal compound, alkali earthmetal or alkali earth metal compound, in the N-type CGL to form a gapstate. As a result, the electron is efficiently transported from theN-type CGL into the ETL.

FIG. 4 is a schematic cross-sectional view of an OLED device accordingto the present invention.

As shown in FIG. 4, an OLED device 100 includes a substrate 110, anorganic light emitting diode D over the substrate 110, and anencapsulation film 120 covering the organic light emitting diode D.

A driving thin film transistor (TFT) Td is disposed on the substrate110, and the organic light emitting diode D is connected to the drivingTFT Td.

A gate line and a data line are disposed on or over the substrate 110and cross each other to define a pixel region. In addition, a powerline, which is parallel to and spaced apart from the gate line or thedata line, a switching TFT, which is electrically connected to the gateline and the data line, and a storage capacitor, which is connected tothe power line and an electrode of the switching TFT may be formed on orover the substrate 110.

The driving TFT Td is connected to the switching TFT and includes asemiconductor layer 152, a gate electrode 160, a source electrode 170and a drain electrode 172.

The semiconductor layer 152 is formed on the substrate 110. Thesemiconductor layer 152 may be formed of an oxide semiconductor materialor a poly-silicon.

When the semiconductor layer 152 includes the oxide semiconductormaterial, a light-shielding pattern may be formed under thesemiconductor layer 152. The light to the semiconductor layer 152 isshielded or blocked by the light-shielding pattern such that thermaldegradation of the semiconductor layer 152 can be prevented. On theother hand, when the semiconductor layer 152 includes polycrystallinesilicon, impurities may be doped into both sides of the semiconductorlayer 152.

A gate insulating layer 154 is formed on the semiconductor layer 152.The gate insulating layer 154 may be formed of an inorganic insulatingmaterial such as silicon oxide or silicon nitride.

The gate electrode 160, which is formed of a conductive material, e.g.,metal, is formed on the gate insulating layer 154 to correspond to acenter of the semiconductor layer 152. The gate electrode 160 isconnected to the switching TFT.

An interlayer insulating layer 162, which is formed of an insulatingmaterial, is formed on an entire surface of the substrate 110 includingthe gate electrode 160. The interlayer insulating layer 162 may beformed of an inorganic insulating material, e.g., silicon oxide orsilicon nitride, or an organic insulating material, e.g.,benzocyclobutene or photo-acryl.

The interlayer insulating layer 162 includes first and second contactholes 164 and 166 exposing both sides of the semiconductor layer 152.The first and second contact holes 164 and 166 are positioned at bothsides of the gate electrode 160 to be spaced apart from the gateelectrode 160.

The source electrode 170 and the drain electrode 172, which are formedof a conductive material, e.g., metal, are formed on the interlayerinsulating layer 162. The source electrode 170 and the drain electrode172 are spaced apart from each other with respect to the gate electrode160 and respectively contact both sides of the semiconductor layer 152through the first and second contact holes 164 and 166. The sourceelectrode 170 is connected to the power line.

In the driving TFT Td, the gate electrode 160, the source electrode 170and the drain electrode 172 are positioned over the semiconductor layer152. Namely, the driving TFT Td has a coplanar structure.

Alternatively, in the driving TFT Td, the gate electrode may bepositioned under the semiconductor layer, and the source and drainelectrodes may be positioned over the semiconductor layer such that thedriving TFT Td may have an inverted staggered structure. In thisinstance, the semiconductor layer may include amorphous silicon.

The switching TFT may have substantially the same structure as thedriving TFT Td.

The OLED device 100 may further include a color filter 190. For example,the color filter 190 absorbs a part of the red, green and blue light. Ared color filter pattern, a green color filer pattern and a blue colorfilter pattern may be disposed in each pixel region. Due to the colorfilter pattern 190, the OLED device 100 provides a full-color image.

In FIG. 4, the color filter 190 is positioned between the light organicemitting diode D and the interlayer insulating layer 162 (or thesubstrate 110). Namely, the OLED device 100 is the bottom-emission type.Alternatively, in the top-emission type OLED device, the color filter190 may be positioned on or over the organic light emitting diode D,e.g., over the second electrode 184. For example, the color filter 190may have a thickness of about 2 to 5 micrometers. The color filter 190may be used with the tandem structure white organic light emitting diodeD in FIG. 2 or FIG. 3.

A passivation layer 174, which includes a drain contact hole 176exposing the drain electrode 172 of the driving TFT Td, is formed tocover the driving TFT Td and the color filter 190.

A first electrode 180, which is connected to the drain electrode 172 ofthe driving TFT Td through the drain contact hole 176, is separatelyformed on the passivation layer 174 in each pixel region.

The first electrode 180 may be an anode and may be formed of aconductive material having a relatively high work function. For example,the first electrode 180 may be formed of a transparent conductivematerial such as ITO, IZO or ZnO.

When the OLED device 100 of the present invention is a top-emissiontype, a reflection electrode or a reflection layer may be formed underthe first electrode 180. For example, the reflection electrode or thereflection layer may be formed of aluminum (Al), silver (Ag), nickel(Ni) or aluminum-palladium-copper (APC) alloy.

A bank layer 186, which covers edges of the first electrode 180, isformed on the passivation layer 174. The bank 186 exposes a center ofthe first electrode 180 in the pixel region.

An organic emitting layer 182 is formed on the first electrode 180. Asexplained below, the organic emitting layer includes a single emittingpart or at least two emitting parts (the tandem structure).

A second electrode 184 is formed over the substrate 110 including theemitting layer 182. The second electrode 184 is positioned at an entiresurface of the display area. The second electrode 184 may be a cathodeand may be formed of a conductive material having a relatively low workfunction. For example, the second electrode 184 may be formed of Al, Mgor Al—Mg alloy.

The first electrode 180, the emitting layer 182 and the second electrode184 constitute the organic light emitting diode D.

The encapsulation film 120 is formed on the organic light emitting diodeD to prevent penetration of moisture into the organic light emittingdiode D. For example, the encapsulation film 120 may has atriple-layered structure of a first inorganic layer, an organic layerand a second inorganic layer. However, it is not limited thereto.

Since the organic compound of the present invention includes the triazincore having three nitrogen atoms, each of which have a rich electronproperty, an electron transporting (or mobility) property of the organiccompound is increased such that the electron is efficiently transportedby the organic compound. In addition, in the organic compound, thebipyridine moiety, which has high electronegativity, is connected(combined or linked) to the triazin core via at least one linker suchthat the electron transporting property of the organic compound isfurther increased.

Moreover, since the nitrogen atom of the triazin core in the organiccompound is combined or bonded with the alkali metal or the alkali earthmetal as a dopant in the ETL or an N-type CGL to form a gap state, theelectron transporting property of the ETL or the N-type CGL is furtherimproved.

Accordingly, when the organic compound is used for at least one of anelectron injection layer (EIL), the ETL and the N-type CGL of an organiclight emitting diode, the electron injection/transporting property inthe organic light emitting diode is increased such that there areadvantages in the driving voltage, the lifetime and the emittingefficiency.

Synthesis 1. Synthesis of the Compound ET_35

Under the nitrogen condition,2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-4,6-diphenyl-1,3,5-triazine(5 g, 13.92 mmol), 5-(10-bromoanthracen-9-yl)-2-(pyridin-3-yl)pyridine(4.75 g, 11.6 mmol), tetrakistriphenylphosphine palladium (0)(Pd(PPh₃)₄) (0.53 g, 0.46 mmol), 4M potassium carbonate aqueous solution(10 mL), toluene (30 mL) and ethanol (10 mL) were refluxed and stirredfor 12 hrs. After completion of the reaction, the distilled water (H₂O,50 mL) was added and stirred for 3 hrs. The mixture was filtered underthe reduced pressure and separated by a column chromatography usingmethylene chloride (MC) and hexane as an eluent. The resultant wascrystallized using MC such that the compound ET_35 (5.30 g, yield 81.2%)was obtained.

2. Synthesis of ET_243

Under the nitrogen condition,2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-4,6-diphenyl-1,3,5-triazine(5 g, 11.49 mmol),2-(4-(4-bromophenyl)-6-(pyridin-2-yl)pyridin-2-yl)pyridine (3.70 g, 9.57mmol), tetrakistriphenylphosphine palladium (0) (Pd(PPh₃)₄) (0.53 g,0.46 mmol), 4M potassium carbonate aqueous solution (10 mL), toluene (30mL) and ethanol (10 mL) were refluxed and stirred for 12 hrs. Aftercompletion of the reaction, the distilled water (H₂O, 50 mL) was addedand stirred for 3 hrs. The mixture was filtered under the reducedpressure and separated by a column chromatography using methylenechloride (MC) and hexane as an eluent. The resultant was crystallizedusing MC such that the compound ET 243 (5.20 g, yield 88.2%) wasobtained.

3. Synthesis of ET_271

Under the nitrogen condition, the compound A (5 g, 9.78 mmol),2-(4-(3-bromophenyl)-6-(pyridin-2-yl)pyridin-2-yl)pyridine (3.15 g, 8.14mmol), tetrakistriphenylphosphine palladium (0) (Pd(PPh₃)₄) (0.53 g,0.46 mmol), 4M potassium carbonate aqueous solution (10 mL), toluene (30mL) and ethanol (10 mL) were refluxed and stirred for 12 hrs. Aftercompletion of the reaction, the distilled water (H₂O, 50 mL) was addedand stirred for 3 hrs. The mixture was filtered under the reducedpressure and separated by a column chromatography using methylenechloride (MC) and hexane as an eluent. The resultant was crystallizedusing MC such that the compound ET_271 (4.88 g, yield 86.7%) wasobtained.

Organic Light Emitting Diode 1. Example 1 (Ex1)

An ITO layer is deposited and patterned on a substrate and washed toform the anode (2 mm*2 mm). The substrate is loaded in a vacuum chamberhaving a base pressure of 5˜7*10⁻⁸, and layers are sequentiallydeposited as below.

(1) HIL: (HAT-CN, 50 Å),

(2) HTL: first layer(NPD+N,N′-diphenyl-N-naphthyl-N′-biphenyl-1,1′-biphenyl-4,4″-diamine(10% doping), 1250 Å) and a second layer (TCTA, 200 Å),

(3) EML: (9,10-di(naphthalen-2-yl)-anthracene+t-Bu-perylene (5% doping),250 Å),

(4) ETL:(2-[4-(9,10-Di-2-naphthalenyl-2-anthracenyl)phenyl]-1-phenyl-1H-benzimidazole,250 Å),

(5) EIL: (ET_243 compound, 100 Å), and

(6) cathode: (Al, 2000 Å)

2. Comparative Example 1 (Ref 1)

Instead of the compound of ET_243, the compound of Bphen(bathophenanthroline).

The EL property of the organic light emitting diode in “Example 1” and“Comparative Example 1” is measured using the current supply “KEITHLEY”and the photometer “PR 650” under the room temperature. The drivingvoltage, the external quantum efficiency (EQE) and the lifetime (T95) ofthe organic light emitting diodes of are measured and listed in Table 1.The current density, the EQE and the lifetime (L/L₀) are shown in FIGS.5A to 5C.

TABLE 1 Current density [10 mA/cm²] Volt [V] EQE T95 Ex 1 100% 101% 107%Ref 1 100% 100% 100%

In comparison to “Comparative Example 1,” Table 1 and FIGS. 5A to 5Cshow that the organic light emitting diode of the present invention(Ex 1) has advantages in the current density, the EQE and the lifetime.

Since the organic compound of the present invention includes the triazincore having three nitrogen atoms, each of which have a rich electronproperty, an electron transporting (or mobility) property of the organiccompound is increased such that the electron is efficiently transportedby the organic compound. In addition, in the organic compound, thebipyridine moiety, which has high electronegativity, is connected(combined or linked) to the triazin core via at least one linker suchthat the electron transporting property of the organic compound isfurther increased. Moreover, since the triazin core and the bipyridinemoiety are separated by the at least one linker, the electronlocalization problem is prevented such that the electron uniformlyexists in the organic compound. Accordingly, when the ETL of the organiclight emitting diode includes the organic compound of the presentinvention, the current from the cathode is efficiently injected into theEML such that there are advantages in the driving voltage, the lifetimeand the emitting efficiency.

Tandem Structure Organic Light Emitting Diode 1. Example 2 (Ex2)

An ITO layer is deposited and patterned on a substrate and washed toform the anode (2 mm*2 mm). The substrate is loaded in a vacuum chamberhaving a base pressure of 5˜7*10⁻⁸, and layers are sequentiallydeposited as below.

(1) HIL: (HAT-CN, 50 Å),

(2) first HTL: first layer(NPD+N,N′-diphenyl-N-naphthyl-N′-biphenyl-1,1′-biphenyl-4,4″-diamine(10% doping), 1250 Å) and a second layer (TCTA, 200 Å),

(3) first EML: (AND+t-Bu-perylene (5% doping), 250 Å),

(4) first ETL:(2-[4-(9,10-Di-2-naphthalenyl-2-anthracenyl)phenyl]-1-phenyl-1H-benzimidazole,250 Å),

(5) first N-type CGL: (ET_35 compound+Li (2% doping), 100 Å),

(6) first P-type CGL: (HAT-CN, 100 Å),

(7) second HTL: first layer (NPD, 400 Å) and second layer (TCTA, 200 Å),

(8) second EML: (BAlq+Ir(2-phq)₃ (10% doping, YG dopant), 300 Å),

(9) second ETL:(2-[4-(9,10-Di-2-naphthalenyl-2-anthracenyl)phenyl]-1-phenyl-1H-benzimidazole,250 GA),

(10) second N-type CGL: (ET_35 compound+Li (2% doping), 100 Å),

(11) second P-type CGL: (HAT-CN, 100 Å),

(12) third HTL: first layer (NPD, 900 Å) and second layer (TCTA, 100 Å),

(13) third EML: (AND+t-Bu-perylene (5% doping), 250 Å),

(14) third ETL:(2-[4-(9,10-Di-2-naphthalenyl-2-anthracenyl)phenyl]-1-phenyl-1H-benzimidazole,350 Å),

(15) EIL: (LiF, 10 Å), and

(16) cathode: (Al, 200 Å)

2. Example 3 (Ex 3)

Instead of the compound of ET_35, the compound of ET_243 is used for thefirst and second N-type CGLs.

3. Example 4 (Ex 4)

Instead of the compound of ET_35, the compound of ET_271 is used for thefirst and second N-type CGLs.

4. Comparative Example 2 (Ref 2)

Instead of the compound of ET_35, the compound of Bphen(bathophenanthroline) is used for the first and second N-type CGLs.

The EL property of the organic light emitting diode in “Example 2” to“Example 4” and “Comparative Example 2” is measured using the currentsupply “KEITHLEY” and the photometer “PR 650” under the roomtemperature. The driving voltage, the external quantum efficiency (EQE)and the lifetime (T95) of the organic light emitting diodes of aremeasured and listed in Table 2. The current density, the EQE and thelifetime (L/L₀) are shown in FIGS. 6A to 6C (comparison of “Ex2” and“Ref 2”), FIGS. 7A to 7C (comparison of “Ex3” and “Ref 2”) and FIGS. 8Ato 8C (comparison of “Ex4” and “Ref 2”).

TABLE 2 Current density [10 mA/cm²] Volt [V] EQE T95 Ex 2 100% 105% 153%Ex 3  93%  97% 143% Ex 4 102% 104% 124% Ref 2 100% 100% 100%

In comparison to “Comparative Example 2,” Table 2 and FIGS. 6A to 6C,FIGS. 7A to 7C and FIGS. 8A to 8C show that the organic light emittingdiode of the present invention (Ex 2 to Ex 4) has advantages in thecurrent density, the EQE and the lifetime. In “Ex2” and “Ex4,” all ofthe properties are improved. In “Ex 3,” the lifetime of the organiclight emitting diode is improved (about 50%).

Since the organic compound of the present invention includes the triazincore having three nitrogen atoms, each of which have a rich electronproperty, an electron transporting (or mobility) property of the organiccompound is increased such that the electron is efficiently transportedby the organic compound. In addition, in the organic compound, thebipyridine moiety, which has high electronegativity, is connected(combined or linked) to the triazin core via at least one linker suchthat the electron transporting property of the organic compound isfurther increased. Moreover, since the triazin core and the bipyridinemoiety are separated by the at least one linker, the electronlocalization problem is prevented such that the electron uniformlyexists in the organic compound. Accordingly, the electron from thecathode or the N-type CGL is efficiently injected into the EML.

Further, since the organic compound of the present invention includesthe nitrogen atom having a relatively electron rich sp² hybrid orbital,the nitrogen atom in the organic compound is combined or bonded with thedopant, e.g., alkali metal, alkali metal compound, alkali earth metal oralkali earth metal compound, in the N-type CGL to form a gap state. As aresult, the electron is efficiently transported from the N-type CGL intothe ETL.

Namely, when the organic compound of the present invention is used forat least one of the EIL, ETL and the N-type CGL, the driving voltage isreduced, the lifetime and the emitting efficiency are improved.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. An organic compound, represented by followingFormula (1):

wherein each of R₁ to R₂ is independently selected from the groupconsisting of hydrogen, substituted C₁-C₂₀ alkyl, non-substituted C₁-C₂₀alkyl, substituted C₁-C₂₀ alkoxy, non-substituted C₁-C₂₀ alkoxy,substituted C₄-C₃₀ cycloalkyl, non-substituted C₄-C₃₀ cycloalkyl,substituted C₄-C₃₀ heterocycloalkyl, non-substituted C₄-C₃₀heterocycloalkyl, substituted C₆-C₆₀ homoaryl, non-substituted C₆-C₆₀homoaryl, substituted C₆-C₆₀ heteroaryl, non-substituted C₆-C₆₀heteroaryl, substituted C₆-C₆₀ homo-oxyaryl, non-substituted C₆-C₆₀homo-oxyaryl, substituted C₆-C₆₀ hetero-oxyaryl, and non-substitutedC₆-C₆₀ hetero-oxyaryl, wherein each of L₁ and L₂ is independentlyselected from the group consisting of substituted C₆-C₆₀ homoarylene,non-substituted C₆-C₆₀ homoarylene, substituted C₆-C₆₀ heteroarylene,and non-substituted C₆-C₆₀ heteroarylene, wherein m is 0 (zero) or 1,and n is 1, wherein one of X₁ to X₄ and X₉ is nitrogen atom, and therest of X₁ to X₄ and X₉ are CH or CR₃, wherein one of X₅ to X₈ and X₁₀is nitrogen atom, and the rest of X₅ to X₈ and X₁₀ are CH or CR₄, andwherein each of R₃ and R₄ is independently selected from the groupconsisting of hydrogen, substituted C₁-C₂₀ alkyl, non-substituted C₁-C₂₀alkyl, substituted C₁-C₂₀ alkoxy, non-substituted C₁-C₂₀ alkoxy, C₁-C₂₀alkyl amino, substituted C₄-C₃₀ cycloalkyl, non-substituted C₄-C₃₀cycloalkyl, substituted C₄-C₃₀ heterocycloalkyl, non-substituted C₄-C₃₀heterocycloalkyl, substituted C₆-C₆₀ homoaryl, non-substituted C₆-C₆₀homoaryl, substituted C₆-C₆₀ homo-oxyaryl, non-substituted C₆-C₆₀homo-oxyaryl, substituted C₆-C₆₀ hetero-oxyaryl, and non-substitutedC₆-C₆₀ hetero-oxyaryl.
 2. The organic compound according to claim 1,wherein each of R₁ and R₂ is phenyl or biphenyl, and each of L₁ and L₂is C₆-C₆₀ homoarylene.
 3. The organic compound according to claim 1,wherein the organic compound is selected from:


4. An organic light emitting diode, comprising: a first electrode and asecond electrode facing each other; an emitting material layer betweenthe first electrode and the second electrode; and an electron injectionlayer between the emitting material layer and the second electrode andincluding the organic compound of claim
 1. 5. The organic light emittingdiode according to claim 4, wherein the electron injection layer furtherincludes an alkali metal, an alkali metal compound, an alkali earthmetal or an alkali earth metal compound.
 6. The organic light emittingdiode according to claim 4, further comprising an electron transportinglayer between the emitting material layer and the electron injectionlayer, wherein the electron transporting layer includes the organiccompound or an electron transporting material doped with the organiccompound.
 7. An organic light emitting diode, comprising: a firstelectrode and a second electrode facing each other; a first emittingpart between the first and second electrodes and including a firstemitting material layer and an electron transporting layer; a secondemitting part between the first emitting part and the second electrodeand including a second emitting material layer; and a first chargegeneration layer between the first emitting part and the second emittingpart, wherein at least one of the electron transporting layer and thefirst charge generation layer includes the organic compound of claim 1.8. The organic light emitting diode according to claim 7, wherein one ofthe first and second emitting parts emits blue, and the other one of thefirst and second emitting parts emits yellow-green.
 9. The organic lightemitting diode according to claim 7, wherein the first charge generationlayer includes a P-type charge generation layer and an N-type chargegeneration layer between the P-type charge generation layer and theelectron transporting layer, and wherein the organic compound isincluded in the N-type charge generation layer, and the N-type chargegeneration layer further includes an alkali metal, an alkali metalcompound, an alkali earth metal or an alkali earth metal compound. 10.The organic light emitting diode according to claim 7, wherein theelectron transporting layer includes the organic compound or an electrontransporting material doped with the organic compound.
 11. The organiclight emitting diode according to claim 7, further comprising: a thirdemitting part between the second emitting part and the second electrodeand including a third emitting material layer; and a second chargegeneration layer between the second emitting part and the third emittingpart, wherein the second charge generation layer includes the organiccompound.
 12. An organic light emitting display device, comprising: asubstrate; the organic light emitting diode of claim 4: and a thin filmtransistor between the substrate and the organic light emitting diodeand connected to the organic light emitting diode.
 13. The organic lightemitting display device according to claim 12, wherein the electroninjection layer further includes an alkali metal, an alkali metalcompound, an alkali earth metal or an alkali earth metal compound. 14.The organic light emitting display device according to claim 12, furthercomprising an electron transporting layer between the emitting materiallayer and the electron injection layer, wherein the electrontransporting layer includes the organic compound or an electrontransporting material doped with the organic compound.
 15. An organiclight emitting display device, comprising: a substrate; the organiclight emitting diode of claim 7: and a thin film transistor between thesubstrate and the organic light emitting diode and connected to theorganic light emitting diode.
 16. The organic light emitting displaydevice according to claim 15, wherein one of the first and secondemitting parts emits blue, and the other one of the first and secondemitting parts emits yellow-green.
 17. The organic light emittingdisplay device according to claim 15, wherein the first chargegeneration layer includes a P-type charge generation layer and an N-typecharge generation layer between the P-type charge generation layer andthe electron transporting layer, and wherein the organic compound isincluded in the N-type charge generation layer, and the N-type chargegeneration layer further includes an alkali metal, an alkali metalcompound, an alkali earth metal or an alkali earth metal compound. 18.The organic light emitting display device according to claim 15, whereinthe electron transporting layer includes the organic compound or anelectron transporting material doped with the organic compound.
 19. Theorganic light emitting display device according to claim 15, furthercomprising: a third emitting part between the second emitting part andthe second electrode and including a third emitting material layer; anda second charge generation layer between the second emitting part andthe third emitting part, wherein the second charge generation layerincludes the organic compound.
 20. The organic light emitting displaydevice according to claim 15, further comprising a color filter betweenthe substrate and the organic light emitting diode or over the secondelectrode.